DNA packaging. Each chromosome consists of one continuous thread-like molecule of DNA coiled tightly around proteins, and contains a portion of the 6,400,000,000 basepairs (DNA building blocks) that make up your DNA. The way DNA is packaged into chromatin is a factor in how protein production is controlled.
Duration: 1 minutes, 30 seconds
In this animation we'll see the remarkable way our DNA is tightly packed up so that six feet of this long molecule fits into the microscopic nucleus of every cell. The process starts when DNA is wrapped around special protein molecules called histones. The combined loop of DNA and protein is called a nucleosome. Next the nucleosomes are packaged into a thread, which is sometimes described as "beads on a string". The end result is a fiber known as chromatin. Now the chromatin fiber is coiled into a structure called a "solenoid". This fiber is then looped and coiled yet again, leading finally to the familiar shapes known as chromosomes, which can be seen in the nucleus of dividing cells. Chromosomes are not always present. They form around the time cells divide when the two copies of the cell's DNA need to be separated. At other times, as we can see now after the cell has divided, our DNA is less highly organized. It is still wrapped up around the histones, but not coiled into chromosomes.
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DNA packaging, 3D animation with advanced narration and labels.
DNA packaging, 3D animation with sound effects only
DNAFTB Animation 29: Roger Kornberg explains his work with Aaron Klug on histones, which bind DNA to form chromatin.
Each chromosome consists of one continuous thread-like molecule of DNA coiled tightly around proteins, and contains a portion of the 6,400,000,000 basepairs (DNA building blocks) that make up your DNA.
DNAFTB Problem 29: Test your understanding of chromosome packaging.
Each chromosome is a package for one very long, continuous strand of DNA.
DNAFTB Animation 7: Walther Flemming explains the phases of mitosis.
DNA is coiled around proteins and packaged as chromatin within the nucleus of cells. Aaron Klug and Roger Kornberg figured out the structure of chromatin. It has been proposed that the coiling (or rather uncoiling) of DNA is a way of controlling the pro
In this section learn that in the cytoplasm, the messenger RNA is released from its carrier proteins and binds to a protein assembly complex called a ribosome.
Sickle cell anemia is a genetic disease that affects hemoglobin, the oxygen transport molecule in the blood.